The present invention is concerned with the application of a metallic powder to a concave surface on a workpiece.
More particularly, the invention is concerned with applying the metallic powder in a substantially regular manner and retaining it in position during subsequent handling of the workpiece, in preparation for heat treating the workpiece.
The invention has utility in the coating field wherein a metallic powder is required to be deposited on the bore of a shaft or ring e.g. for the purpose of providing a bearing surface. Alternatively, a metallic powder could be deposited in accordance with the invention, on a workpiece bore, so as to provide means whereby a further member can be joined to the workpiece i.e. to provide a layer of braze material on the bore, and thereafter brazing a further member to it.
One known method of applying a metallic powder to a surface in a regular manner which could be adopted irrespective of the shape of the surface, is described in British Pat. No. 1,334,683. The method disclosed therein, requires the application of a layer of tacky adhesive to the workpiece surface, prior to application of the powder. However, this disclosure is limited to the application of a single layer of powder. Should extra layers be required to build up a specific thickness not achievable by mere choice of the magnitude of powder particles, the process must be repeated. Each consecutive layer of powder will need the application of adhesive, prior to having a further powder layer superimposed thereon.
It is an object of the present invention to provide a method of applying a powder material to the wall of a bore in a workpiece and retaining it there, which method enables rapid application in a regular manner, of one or more layers of the powder.
It is a further object of this invention to provide a method of brazing an arcuate honeycomb structure to the wall of a bore in a workpiece, using a metallic braze powder which is applied by the method of the present invention.
A further object of the invention, is to provide apparatus with which powder material is applied to the wall of a bore in a workpiece, by the method of the present invention.